Chromium (VI) reagents have been widely used in organic chemistry for the oxidation of primary and secondary alcohols to carbonyl compounds. Pyridine-chromium trioxide complexes, pyridinium chlorochromate and bipyridine-chromium trioxide complexes have been especially useful reagents for the mild oxidation of primary alcohols to aldehydes. There are, however, some significant difficulties associated with these reagents. For instance, chromium containing by-products often contaminate the desired products, requiring time-consuming purifications. Also, polymeric chromium containing tars may be formed which contaminate both the reaction and work-up apparatus. In addition, to date, little useful selectivity has been observed in the oxidation of polyhydroxy compounds using chromium (VI) oxidizing reagents.